We introduced a simple technique to eliminate electromagnetic interference between a left ventricular assist device (LVAD) and an implantable cardioverter-defibrillator (ICD). A 43-year-old male with heart failure and a reduced ejection fraction (HFrEF) who had an ICD presented with decompensated heart failure and received an LVAD as a bridge to transplant. Remote monitoring showed persistent atrial fibrillation causing an inappropriate ICD shock leading to a decision to disable shock therapies. However, an in-office interrogation was unsuccessful due to electromagnetic interference. Patient was instructed to extend his arm above his head on the ipsilateral side of the ICD, thus increasing the distance between LVAD and ICD, eliminating the interaction to allow reprogramming of the device.

Background: Although catheter ablation (CA) is an effective treatment for patients with AF and LVSD, the efficacy of an initial cryo-ablation strategy is unknown. This study evaluated long term outcomes of patients with an initial cryo-ablation strategy for AF and LV systolic dysfunction (LVSD). Methods: Outcomes of patients undergoing index cryoablation for AF from January 2008 until March 2018, with documented pre-ablation LVEF45% were evaluated for long term freedom from AF and change in ventricular function from baseline. Results: 76 patients met inclusion criteria. Patients were predominantly male (80%), aged 63 11yrs, with an average CHADS2 VASc score of 2.66  1.40, baseline LVEF 34  8.7% (ischaemic in 37%) and NYHA class 2.37  0.72. Repeat procedures were performed in 13%. The single procedure success was 70% at 1 year (81% for paroxysmal AF, 65% for persistent AF, 29% for long-standing persistent AF) and at 28  13 months follow up was 43% (50%, 41% and 21% respectively), increasing to 59% allowing for subsequent redo procedure with RF ablation (64%, 57%, and 50% respectively). At follow up, LVEF significantly improved to 46  16% (p<0.001), and NYHA reduced to 1.51  0.66 (p<0.001). Conclusion: An initial strategy of cryoablation in patients with AF and LVSD is an effective approach in the treatment of patients with concurrent AF and LVSD. Larger, randomised prospective studies are required to confirm these findings.

Aims: Catheter ablation (CA) for atrial fibrillation (AF) has a considerable risk of procedural complications. Major vascular complications (MVCs) appear to be the most frequent. This study investigated gender differences in MVCs in patients undergoing CA for AF. Methods: A total of 4734 CAs for AF (65% paroxysmal, 26% repeated procedures) were performed at our center between January 2006 and August 2018. Patients (71% males) aged 60 ± 10 years and had body mass index of 29 ± 4 kg/m2. Radiofrequency point-by-point ablation was employed in 96.3% procedures with the use of 3D navigation systems and facilitated by intracardiac echocardiography. Pulmonary vein isolation was mandatory; cavotricuspid isthmus and left atrial substrate ablation were performed in 22% and 38% procedures, respectively. MVCs were defined as those that resulted in permanent injury, required intervention, or prolonged hospitalization. Their rates and risk factors were compared between genders. Results: A total of 112 (2.4%) MVCs were detected: 54/1512 (3.5%) in females and 58/3222 (1.8%) in males (P < 0.0001). On multivariate analysis, lower body height was the only risk factor for MVCs in females (P = 0.0005). On the contrary, advanced age was associated with MVCs in males (P = 0.006). Conclusion: Females have a higher risk of MVCs following CA for AF compared to males. This difference is driven by lower body size in females. Low body height in females and advanced age in males are independent predictors of MVCs. US-guided venipuncture lowered the MVC rate in males.

Wide complex tachycardia with changing QRS-axis on loop recorderShort title: QRS-axis changes on loop recorder

Introduction: Presence of preferential pathway conduction is mostly detected as fractionated presystolic potentials preceding the QRS onset during premature ventricular contractions (PVCs) and late potentials during sinus rhythm (SR), but the electrophysiologic mechanisms and significance of these potentials have not been fully clarified. We describe a PVC case series in which the preferential pathway conduction was 3-dimensionaly visualized by coherent mapping with the conduction velocity vector. Methods: Five PVCs (2 from the left coronary cusp, 2 from the commissure of the left and right coronary cusps, and 1 from the pulmonary artery) in 4 patients for which a fractionated presystolic potential during the PVCs and late potential during SR were recorded at the successful ablation site were reviewed, and 3-dimensional coherent activation maps with the conduction velocity vector during the PVCs and SR were reconstructed. Results: At the successful ablation site, an “M”-shaped discrete presystolic-potential and “W”-shaped discrete late-potential were recorded in all patients. The configuration of the flipped electrogram of the presystolic-potential nearly matched that of the electrogram exhibiting the late-potential. We created coherent activation maps annotating the onset of the presystolic potentials during the PVCs, and the offset of the late potentials during SR, which suggested bidirectional conduction of the preferential pathway connecting the PVC origin to the myocardium. Conclusion: In this case series, the M-shaped presystolic potential and W-shaped late potential were reversely matched. These reverse potentials, and the coherent activation vector maps during PVCs and SR suggested bidirectional conduction of the preferential pathway in opposite directions.

Introduction: Elevated left atrial pressure (LAP) during catheter ablation of atrial fibrillation (AF) is associated with an increased risk of AF recurrence, but it is unknown if this correlates with heart failure (HF). The objective of the study was to determine if elevated LAP after AF ablation correlates with HF events. Methods: Prospective, single center, cohort study measuring LAP and RAP during AF ablation in 100 patients. The primary endpoint was clinical HF within 30 days of ablation. The secondary outcome was AF-free HF. Results: 100 patients (63% male, mean age 64.5) were enrolled and 20% had clinical HF within 30 days. Bivariate correlates included mitral valve (MV) disease, persistent AF, class III antiarrhythmics, LAP, and recurrent AF. Multivariate analysis revealed class III antiarrhythmics were protective (OR 0.24 [0.1–0.5], p=0.04), while MV disease (OR 8.7 [3.3—23], p=0.03) and loop diuretics (OR 4.8 [2.6–9.1], p=0.01) were hazardous. AF-free HF occurred in 9% of patients and correlated with higher LAP and RAP, and CKD. Conclusion: Patients with HF after AF ablation had higher LAP. MV disease, diuretic use, and class III antiarrhythmics also correlated to HF. These present opportunities to target future interventions to reduce a common complication of AF ablation.

RESPONSE FOR THE LETTER TO THE EDITORDon’t miss a chance taking the best shot!!Kunihiko KiuchiDivision of Cardiovascular Medicine, Department of Internal Medicine, Kobe University Graduate School of MedicineAddress for correspondence:Kunihiko Kiuchi, MD, FHRSSection of Arrhythmia, Division of Cardiovascular Medicine,Department of Internal Medicine, Kobe University Graduate School of Medicine7-5-2 Kusunoki-chou chuou-ku, Kobe, Hyogo, JapanTelephone: (81)-78-382-5846Fax: (81)-78-382-5859E-mail: [email protected]:The Section of Arrhythmia was supported by an endowment from Medtronic JAPAN and Abbott JAPAN. The authors have reported that they have no relationships relevant to the contents of this paper to disclose.Funding: NoneTo the Editor,We thank Dr. Althoff and Mont for their interest, comments, and suggestions related to our paper.1 In our study, as they suggested, LGE-MRI was acquired 1-3 months after the ablation. An animal study reported that ablation lesions are fully formed by 3 weeks and are dense with collagen and fat deposition by 6 weeks.2 In our pilot study, the ablation lesion area dramatically diminished from 1 week to 6 weeks after the procedure in most of the patients. Furthermore, the ablation lesion area was comparable between 6 weeks and just 3 months after the ablation. Of interest, the ablation lesion disappeared after 5-6 months following the procedure in some patients without AF recurrence. We speculated that the shrinkage of the ablation lesion might have occurred during the pathophysiological healing process and reverse remodeling of the left atrium. Therefore, we considered that the time point of taking the “best shot” might have been earlier than we expected. Furthermore, the dose of the contrast agent was important for determining the time point. Our dose of the contrast agent was 0.1mmol/kg, which was relatively lower than that of the other groups. To address this issue, further study will be needed.As for an internal reference for normalization, the threshold of the signal intensity was initially determined according to the signal intensity histogram on the “whole LA wall” in our previous studies.3,4 However, as the authors suggested, neither the ablation lesion nor atrial fibrosis could be accurately visualized in some patients with advanced atrial remodeling. Therefore, the internal reference was changed from the “whole LA wall” to the “healthy LA wall” in our recent studies.1,5 We believed that this simple but important tip might make it possible to sensitively identify pre-existing atrial fibrosis, particularly interstitial fibrosis. The signal intensity of ablation lesion was significantly higher than that of the pre-existing atrial fibrosis. Our question is whether the ablation lesion characteristics dramatically differed between the different references in patients without atrial remodeling. Although we re-analyzed the LGE-MRI with two different references (“whole LA wall” and “healthy LA wall”), no significant difference in the lesion characteristics could be found. Cryoballoon ablation and RF ablation with contact-force sensing catheter induced intensive inflammation which followed by the artificial fibrosis.6 In this study, we focused on the visualization of the ablation lesion not the pre-existing atrial fibrosis, and patients without atrial remodeling were enrolled. We considered that the impact of the difference in the reference could be less than we expected, when we focused on the ablation lesions in patients without atrial remodeling.To visualize the atrial fibrosis and the ablation lesion, different visualization methods were developed. However, very few histological validations could be found. Furthermore, the dose of the contrast agents, MRI system, and visualization software completely differed due to the regulations in each institution. Therefore, it is not surprising that the image differed between each visualization technique. It is important to note the reproducibility of the visualization method and clinical implication of the best shot. The authors had already reported the reproducibility of their method.7 However, this issue is still in debate.8 We would like to challenge to improve the quality of our “best shot” and strengthen both reproducibility and clinical implication in a further study.References1. Kurose J, Kiuchi K, Fukuzawa K, et al. Lesion characteristics between cryoballoon ablation and radiofrequency ablation with a contact-force sensing catheter: late-gadolinium enhancement magnetic resonance imaging assessment. J Cardiovasc Electrophysiol. 2020.2. Avitall B, Kalinski A. Cryotherapy of cardiac arrhythmia: From basic science to the bedside. Heart Rhythm. 2015;12(10):2195-2203.3. Shigenaga Y, Kiuchi K, Ikeuchi K, et al. Fusion of Delayed-enhancement MR Imaging and Contrast-enhanced MR Angiography to Visualize Radiofrequency Ablation Scar on the Pulmonary Vein. Magn Reson Med Sci. 2015;14(4):367-372.4. Kiuchi K, Okajima K, Shimane A, et al. Visualization of the radiofrequency lesion after pulmonary vein isolation using delayed enhancement magnetic resonance imaging fused with magnetic resonance angiography. J Arrhythm. 2015;31(3):152-158.5. Akita T, Kiuchi K, Fukuzawa K, et al. Lesion distribution after cryoballoon ablation and hotballoon ablation: Late-gadolinium enhancement magnetic resonance imaging analysis. J Cardiovasc Electrophysiol. 2019.6. Kiuchi K, Fukuzawa K, Mori S, Watanabe Y, Hirata KI. Feasibility of Imaging Inflammation in the Left Atrium Post AF Ablation Using PET Technology. JACC Clin Electrophysiol. 2017;3(12):1466-1467.7. Benito EM, Carlosena-Remirez A, Guasch E, et al. Left atrial fibrosis quantification by late gadolinium-enhanced magnetic resonance: a new method to standardize the thresholds for reproducibility.Europace. 2017;19(8):1272-1279.8. Kamali R, Schroeder J, DiBella E, et al. Reproducibility of Clinical Late Gadolinium Enhancement Magnetic Resonance Imaging in Detecting Left Atrial Scar after Atrial Fibrillation Ablation. J Cardiovasc Electrophysiol. 2020 in press.

A document by William Chan. Click on the document to view its contents.

Objective: To determine trends in real-world utilization and in-hospital adverse events from Watchman implantation since its approval by the Food and Drug Administration in 2015. Background: The risk of embolic stroke caused by atrial fibrillation is reduced by oral anticoagulants, but not all patients can tolerate long-term anticoagulation. Left atrial appendage occlusion with the Watchman device has emerged as an alternative therapy. Methods: This was a retrospective cohort study utilizing data from National Inpatient Sample for calendar years 2015-2017. The outcomes assessed in this study were associated complications, in-hospital mortality, and resource utilization trends after Watchman implantation. Trends analysis were performed using analysis of variance. Multivariable adjusted logistic regression analysis was performed to determine predictors of mortality. Results: A total of 17,700 patients underwent Watchman implantation during the study period. There was a significantly increased trend in the number of Watchman procedures performed over the study years (from 1,195 in 2015 to 11,165 devices in 2017, p < 0.01). A significant decline in the rate of complications (from 26.4% in 2015 to 7.9% in 2017, p < 0.01) and inpatient mortality (from 1.3% in 2015 to 0.1% in 2017, p < 0.01) were noted. Predictors of in-hospital mortality included a higher CHA₂DS₂-VASc score (OR 2.61 per 1-point increase, 95% CI 1.91-3.57), chronic blood loss anemia (OR 3.63, 95% CI 1.37-9.61) and coagulopathy (OR 4.90, 95% CI 2.32-10.35). Conclusion: In contemporary United States clinical practice, Watchman utilization has increased significantly since approval in 2015, while complications and in-patient mortality have declined.

Coronary artery injury is a rare complication of catheter ablation in the right ventricular outflow tract (RVOT). Furthermore, acute myocardial ischemia usually causes polymorphic ventricular tachycardia (VT) or ventricular fibrillation. We herein describe a case in which catheter ablation for VT originating from the RVOT provoked ischemia-related VTs due to acute occlusion of the left anterior descending artery.

Is Otsu Thresholding the Answer to Reproducible Quantification of Left Atrial Scar from Late Gadolinium-Enhancement MRI?Suvai Gunasekaran, PhDa, Daniel Kim, PhDa,ba Department of Radiology, Northwestern University Feinberg School of Medicine, Chicago, IL, United Statesb Department of Biomedical Engineering, Northwestern University, Evanston, IL, United StatesPlease send correspondence to:Daniel Kim, PhDDepartment of RadiologyNorthwestern University737 N. Michigan Avenue Suite 1600Chicago, IL 60611 [email protected] O:312.926.1733 F:312.926.5991

Objectives: The aim of this analysis was to evaluate the predictors associated with increased risk of permanent pacemaker implantation (PPMI) following Transcatheter Aortic Valve Replacement (TAVR). Background: While TAVR has evolved as the standard of care for patients with severe aortic stenosis, conduction abnormalities leading to the need for PPMI is one of the most common post-procedural complications. Methods: A systematic literature search was performed to identify relevant trials from inception to May 2020. Summary effects were calculated using a DerSimonian and Laird random-effects model as odds ratio with 95% confidence intervals for all the clinical endpoints. Results: 37 observational studies with 71,455 patients were identified. The incidence of PPMI following TAVR was 22%. Risk was greater in men and increased with age. Patients with diabetes mellitus, presence of right bundle branch block, baseline atrioventricular conduction block, and left anterior fascicular block were noted to be at higher risk. Other significant predictors include the presence of high calcium volume in the area below the left coronary cusp and non-coronary cusp, use of self-expandable valve over balloon-expandable valve, depth of implant, valve size/annulus size, pre-dilatation balloon valvuloplasty and post-implant balloon dilation. Conclusion: Fourteen factors were found to be associated with increased risk of PPMI after TAVR, suggesting early identification of high-risk populations and targeting modifiable risk factors may aid in reducing the need for this post TAVR PPMI.

Introduction Left atrial posterior wall (LAPW) isolation may be performed as an additional atrial fibrillation (AF) ablation strategy based on pulmonary vein isolation. A modified posterior-inferior line (MPL) was proposed for reducing esophageal injury. The aim of this study was to evaluate the anatomical characteristics of the MPL, compared with the CPL. Methods and Results Multidetector computed tomography was performed in 102 consecutive AF patients (male/female = 60/42) preoperative, and the parameters were evaluated as follows: the distance from MPL and CPL to the esophagus, fat pad presence and thickness in the course of MPL and CPL, and the esophageal route below CPL. The average distance from the MPL to the esophagus was longer than from CPL to the esophagus (3.7 ± 1.5mm vs 1.7 ± 0.4mm, P < 0.001). Fat pad presence was higher in the course of MPL than CPL. The myocardium tissue and fat pad under MPL was thicker than under CPL (2.9 ± 1.1mm vs 1.6 ± 0.3mm, P < 0.001; 1.4 ± 0.6mm vs 0.9 ± 0.2mm, P < 0.001), respectively. In patients whose esophagus was unconfined in a triangular space at the left inferior pulmonary vein level, the average distance from MPL to esophagus was longer than the confined patients (4.0 ± 1.7mm vs 3.2 ± 1.0mm, P = 0.001). Conclusion The MPL was far away from the esophagus with thicker myocardium tissue and more fat pad than the CPL; thus, MPL could serve as a favorable alternative in linear ablation for LAPW isolation.

A document by Pedro Brugada. Click on the document to view its contents.

Background: Multiple strategies have advocation for power titration and catheter movement during atrial fibrillation (AF) ablation. Comparative favoring evidence regarding the efficacy, logistics, and safety of a higher power, shorter duration (HPSD) ablation strategy compared to a lower power, longer duration (LPLD) ablation strategy is insubstantial. We performed a meta-analysis to compare arrhythmia-free survival, procedure times, and complication rates between the two strategies. Methods: We searched MEDLINE, EMBASE and Cochrane Library from inception to April 2020. We included studies comparing patients underwent HPSD and LPLD strategies for AF ablation and reporting either of the following outcomes: freedom from atrial tachyarrhythmia (AT) including AF and atrial flutter, procedure time, or periprocedural complications. We combined data using the random-effects model to calculate odds ratio (OR) and weight mean difference (WMD) with 95% confidence interval (CI). Results: Nine studies from 2006-2020 involving 2,282 patients were included (1,369 patients underwent HPSD strategy and 853 patients underwent LPLD strategy). HPSD strategy was not associated with an increased freedom from AT at 12-month follow-up (OR= 1.41, 95%CI:0.90-2.21). There was a significant reduction in the HPSD group for total procedure (WMD=49.60, 95%CI:29.76-69.44) and ablation (WMD=17.92, 95%CI:13.63-22.22) times, but not for fluoroscopy time (WMD=1.15, 95%CI:-0.67-2.97). HPSD was not associated with a reduction in esophageal ulcer/atrioesophageal fistula (OR=0.35, 95%CI:0.12-1.06) or pericardial effusion/cardiac tamponade rates (OR=0.96, 95%CI:0.24-3.79). Conclusions: When compared to a LPLD strategy, HPSD strategy does not improve recurrent AT nor reduce periprocedural complication risks. However, a HPSD strategy can significantly reduce total procedure and ablation times.

Kurose et al. report on a lower number of gaps in RF-lesions compared to Cryo-lesions as determined by late gadolinium enhancement MRI (LGE-MRI). However, unlike claimed by the authors, there is ample evidence based on LGE-MRI in this context. Most importantly we have specifically compared RF and Cryo lesions in a recent case control study on AF Ablation. In contrast to the results of Kurose et al., our study, despite larger sample size, did not detect a difference in the number of gaps between the two energy sources. While numerous factors may account for the conflicting results, two points should be considered in particular. 1. The time point of LGE-MRI at a mean of 55 days post ablation has never been validated for chronic lesion formation, and is considerably earlier than the validated and well-established 3-months timepoint chosen by most groups. In fact, according to previous reports, gadolinium enhancement at earlier time points may, at least in part, reflect a transient inflammatory response rather than chronic scar formation. 2. The method of Kurose et al. is based on the definition of an area of healthy atrial tissue in each patient as an internal reference. However, it appears almost impossible to define a truly healthy area in the atrium of patients with atrial fibrillation. Thus the method is likely to underestimate ablation-induced fibrosis in patients with advanced disease and/or underlying pathologies and to overestimate it in younger, rather healthy patients.

Introduction: Hemodynamics of left atrial appendage (LAA) is an important factor for future risk of ischemic stroke in atrial fibrillation (AF) patients and velocity encoded cardiac magnetic resonance imaging (VENC-MRI) can evaluate blood flow volume of LAA without any invasive procedures. We aimed to evaluate the impact of radiofrequency catheter ablation (RFCA) on LAA hemodynamics via MRI evaluation. Methods and Results: Consecutive RFCA cases in a single arrhythmia center were retrospectively analyzed. A total of 3,120 AF patients who underwent first RFCA were analyzed. Among these patients 360 patients had both pre- and post-RFCA VENC-MRI evaluation. Atrial fibrillation was non-paroxysmal in 174 (48.3%) patients. Mean VENC-MRI (ml/sec) was significantly improved after RFCA with 49.75±32.97 and 71.92±34.94 for pre- and post-RFCA, respectively. Patients with non-paroxysmal AF (∆VENC-MRI = 29.71±35.30 vs. 14.42±40.94; p < 0.001) and low pre-RFCA VENC-MRI (∆VENC-MRI = 50.64±28.92 vs. 16.72±38.39; p < 0.001) had significantly higher improvement in VENC-MRI. Those who experienced late recurrence before post-RFCA MRI had significantly less improvement in LAA flow volume (∆VENC-MRI = 15.55±41.41 vs. 25.75±37.00; p = 0.016). Similar results were obtained after adjusting covariates. Conclusions: Radiofrequency catheter ablation can significantly improve hemodynamics of LAA in AF patients. The beneficial effects were most prominent in non-paroxysmal AF, those who had low pre-RFCA VENC-MRI, and those without late recurrence. Whether the improved hemodynamics of LAA after RFCA actually leads to reduced risk of ischemic stroke should be evaluated in future trials.

Introduction Left bundle branch area pacing (LBBAP) aims to achieve physiological pacing by capturing the conduction system in the area of the left bundle branch. LBBAP has exclusively been performed using lumen-less pacing leads (LLL) with fixed helix design. This study explores the feasibility, safety and pacing characteristics of LBBAP using stylet-driven leads (SDL) with an extendable helix design. Methods Patients, in which LBBAP was attempted for bradycardia or heart failure pacing indications, were prospectively enrolled at the Ghent University Hospital. LBBAP was attempted with two different systems: 1/ LLL with fixed helix (SelectSecure 3830, Medtronic, Inc) delivered through a preshaped sheath (C315His Medtronic) and 2/ SDL with extendable helix (SoliaS60, Biotronik, SE & CO) delivered through a new delivery sheath (Selectra 3D, Biotronik). Results The study enrolled 50 patients (mean age 7014 years, 44% female). LBBAP with SDL was successful in 20/23 (87%) patients compared to 24/27 (89%) of patients in the LLL group (p=0.834). Screw attempts, screw implant depth, procedural and fluoroscopy times were comparable among both groups. Acute LBBAP thresholds were low and comparable between SDL and LLL (0.50.15V versus 0.40.17V, p=0.251). Pacing thresholds remained low at 32.1 months of follow up in both groups and no lead revisions were necessary. Post procedural echocardiography revealed a septal coronary artery fistula in one patient with SDL LBBAP. Conclusion LBBAP using stylet-driven pacing leads is feasible and yields comparable implant success to LBBAP with lumen-less pacing leads. LBBAP thresholds are low and comparable with both types of leads.